The proper control of gene expression requires the processes o transcription and RNA processing. The molecular mechanisms of each of these processes have been examined in great detail. What is lacking is an understanding of the precise nuclear locations at which each one of these events takes place relative to one another. In mammalian cells in situ hybridization experiments have revealed that transcription and splicing occur in close proximity to one another. No information concerning the physical relationship between transcription and splicing in the yeast nucleus exists. The goal of the study is to define the nuclear position of transcription and RNA processing in the yeast S. cerevisiae as follows. 1,) Refinement of the protocol for fluorescence in situ hybridization for a specific RNA transcript will continue in order to detect transcripts from a single copy gene as well as sites of transcription. 2) By digital imaging microscopy and simultaneous dual color fluorescence in situ hybridization, the relationship between sites of transcription and RNA processing will be examined both spatially and temporally. 3.) Methodology will be refined for in situ hybridization in yeast by detection in the electron microscopy. The genetic tools available is yeast combined with in situ hybridization will allow for a greater depth of research than that available in higher eukaryotic cells.